1. Field
This application relates generally to systems and methods for accelerating tissue processing. More specifically, this application relates to systems and methods for accelerating tissue fixation, dehydration, and/or other aspects of tissue processing through the use of infrasonic vibrations.
2. Background
Tissue samples may include one or more cells, tissues, organs, or other materials obtained from an organism, as well as the entire organism or a portion thereof. Such tissue samples may be useful in the study and practice of medicine, histology, pathology, cellular biology, and the biological sciences in general. For instance, tissue samples may be useful for the diagnosis of disease or may aid in the study of diseases, disorders, functions, structures, and other characteristics of biological specimens. Although tissue samples may be obtained in many ways, including from autopsy, biopsy, surgery, necropsy, etc., once obtained, the samples are often unable to regulate proteolytic enzymes and other processes that tend to break down and degrade biological material.
In order to preserve a sample's structure or morphology, as well as to conserve the presence and reactivity of biochemicals in the sample, tissue samples are often processed to be preserved by freezing or by chemical fixation. Where a sample is frozen, the sample is often frozen, cut, and mounted to a slide in a short period of time, such as about 15 minutes. This frozen section procedure can allow for rapid histological diagnosis to be made from a sample. As a result, this process is frequently used in situations where a diagnosis is necessary during a surgical operation. However, this frozen section procedure can also have certain disadvantages. For example, samples prepared by this procedure may not possess the same level of uniformity and quality as samples prepared by another process. Similarly, samples prepared by this frozen section procedure may need to be extra thick and require special stains that are difficult to use. Moreover, this frozen section procedure may cause other artifacts associated with freezing and may put the sample at a high risk of being damaged by thawing or refreezing. For at least the aforementioned reasons, this frozen section procedure may reduce the quality of the tissue samples and cause the processed samples to lack important detail.
Generally, fixation is a chemical process that prevents tissue sample decay by terminating ongoing biochemical reactions. This process may also increase the mechanical strength or stability of the treated samples. There are many fixation processes as well as reagents. For instance, tissue samples may be fixed with a cross-linking fixative, such as an aldehyde-based fixative, that is believed to react with proteins and other molecules in the tissue sample to form methylene bridges. The methylene bridges may produce a network of chemical bonds that can prevent the movement of large molecules, such as proteins, and substantially preserve the physical structure of the tissue sample. After fixation, destructive enzymes may be prevented from further degrading the tissue sample.
In addition to tissue fixation, tissue processing may involve several additional stages that further preserve the tissue sample or prepare it for examination. For instance, the fixed tissue sample may be dehydrated, cleared, impregnated with and embedded in a material (e.g., paraffin or gelatin), cut into sections, cleared, mounted to a slide, stained, treated with enzymes, treated with antibodies, treated for antigen retrieval, and/or otherwise be prepared for microscopic examination.
Although tissue processing methods that involve fixation may allow tissue samples to be studied long after the natural expiration of the samples would have occurred, these methods are not without shortcomings. For instance, artifacts may be produced by incomplete fixation. Additionally, some conventional tissue processing methods that involve fixation may be quite time consuming and require processing times that last from several hours to several days.
To speed conventional tissue processing methods that include fixation, some have implemented one or more additional processing steps. In one example, some have begun using ultrasonic vibrations to speed tissue processing. However, in certain circumstances, these ultrasonic vibrations can focally overheat and damage the tissue sample. In another example, some have begun heating or microwaving the tissue sample at different tissue processing steps. However, because temperatures above 37° Celsius can unfold, refold, aggregate, and/or denature proteins within the sample, such heating and microwaving steps may locally overheat and damage the tissue sample. Indeed, many conventional methods to speed tissue processing may damage tissue samples, damage cell morphology, cause DNA/RNA degradation, require antigen retrieval, cause additional artifacts, or otherwise impede proper tissue analysis.
Thus, while techniques currently exist that are used to speed tissue processing (i.e., fixation), challenges still exist, including those listed above. Accordingly, it would be an improvement in the art to augment or even replace current techniques with other techniques that speed tissue processing and, which may more thoroughly fix a tissue sample or otherwise improve the sample's detail.